Heretofore, generally undesirable quantities of cadmium-based stabilizers were found useful as stabilizers for vinyl polymers, particularly polyvinyl chloride. The art sought to avoid the extensive use of large quantities of cadmium-based stabilizers, and thus sought other possible stabilizers for vinyl halide resins.
In the patent to Coates, U.S. Pat. No. 3,925,246, granted Dec. 9, 1975, there are disclosed certain sulfur containing esters for use as costabilizers with organotin stabilizers for halogen containing resins.
Heckenbleikner, et al, U.S. Pat. No. 3,839,507, granted Oct. 1, 1974, disclose thiophosphate and thiophosphite esters as antioxidants and stabilizers against heat and light for halogen containing resins.
Kopacki, et al. U.S. Pat. No. 3,542,725, disclose certain thiol stabilizers derived from thiol acids for vinyl polymers.
While such prior art stabilizer systems were somewhat successful, the prior art desired a more effective polyvinyl halide stabilizer system.
It is, therefore, a principal object of the present invention to provide an effective stabilizer for polymers, particularly the halogen containing resins.
It is a further object of the present invention to proide a stabilizer as aforesaid which avoids the extensive use of cadmium compounds.
It is a still further object of the present invention to provide a novel costabilizer system which is highly effective for vinyl halide resins.
It is a still further object of the present invention to provide a stabilizer which is readily incorporated in and highly effective in flexible polyvinyl chloride resins.